TY - JOUR
T1 - Adjusting the energy of interfacial states in organic photovoltaics for maximum efficiency
AU - Gasparini, Nicola
AU - Camargo, Franco V. A.
AU - Frühwald, Stefan
AU - Nagahara, Tetsuhiko
AU - Classen, Andrej
AU - Roland, Steffen
AU - Wadsworth, Andrew
AU - Gregoriou, Vasilis G.
AU - Chochos, Christos L.
AU - Neher, Dieter
AU - Salvador, Michael
AU - Baran, Derya
AU - McCulloch, Iain
AU - Görling, Andreas
AU - Lüer, Larry
AU - Cerullo, Giulio
AU - Brabec, Christoph J.
N1 - KAUST Repository Item: Exported on 2021-03-22
Acknowledgements: N.G. acknowledges the Imperial College Research Fellowship scheme. C.J.B. gratefully acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project no. 182849149-SFB 953. C.J.B. gratefully acknowledges financial support through the “Aufbruch Bayern” initiative of the state of Bavaria (EnCN and SFF) and the Bavarian Initiative “Solar Technologies go Hybrid” (SolTech) and funding from DFG project DFG INST 90/917. C.C.L. thanks the European Union for the financial support. G.C. acknowledges the support from the PRIN 2017 Project 201795SBA3—HARVEST.
PY - 2021/3/19
Y1 - 2021/3/19
N2 - AbstractA critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in the interfacial charge-transfer (CT) state via the formation of hybrid energetic states. This requires small energetic offsets often detrimental for high external quantum efficiency (EQE). Here, we obtain OSC with both non-radiative voltage losses (0.24 V) and photocurrent losses (EQE > 80%) simultaneously minimised. The interfacial CT states separate into free carriers with ≈40-ps time constant. We combine device and spectroscopic data to model the thermodynamics of charge separation and extraction, revealing that the relatively high performance of the devices arises from an optimal adjustment of the CT state energy, which determines how the available overall driving force is efficiently used to maximize both exciton splitting and charge separation. The model proposed is universal for donor:acceptor (D:A) with low driving forces and predicts which D:A will benefit from a morphology optimization for highly efficient OSC.
AB - AbstractA critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in the interfacial charge-transfer (CT) state via the formation of hybrid energetic states. This requires small energetic offsets often detrimental for high external quantum efficiency (EQE). Here, we obtain OSC with both non-radiative voltage losses (0.24 V) and photocurrent losses (EQE > 80%) simultaneously minimised. The interfacial CT states separate into free carriers with ≈40-ps time constant. We combine device and spectroscopic data to model the thermodynamics of charge separation and extraction, revealing that the relatively high performance of the devices arises from an optimal adjustment of the CT state energy, which determines how the available overall driving force is efficiently used to maximize both exciton splitting and charge separation. The model proposed is universal for donor:acceptor (D:A) with low driving forces and predicts which D:A will benefit from a morphology optimization for highly efficient OSC.
UR - http://hdl.handle.net/10754/668161
UR - http://www.nature.com/articles/s41467-021-22032-3
U2 - 10.1038/s41467-021-22032-3
DO - 10.1038/s41467-021-22032-3
M3 - Article
C2 - 33741966
SN - 2041-1723
VL - 12
JO - Nature Communications
JF - Nature Communications
IS - 1
ER -